As examples of conventional heating seats, there have been heating seats in which a seat heater is placed between a cushion member for seats and a skin material covering it, as seen in seats installed in automobiles (e.g., see Patent Literature 1).
Such a seat heater is installed in automobiles or the like in order to improve comforts during the cold season. However, from the viewpoint of energy saving, it is desirable that the function of the heater be provided with a smaller amount of power.
Especially in recent years, distribution of electric vehicles has been demanded. As a result, it is required that the energy efficiency be increased as nigh as possible, thereby providing a heater with less power consumption. Therefore, this is a quite important technique, since this leads to an increase in the driving range. In such a viewpoint, it can be considered that railroad vehicles and airplanes also suffer from the same problem.
FIG. 9 is a cross-section view of a conventional heating seat 901. A skin 903 is placed to cover the upper side of a cushion member 902 of the seat 901 installed in an automobile. A seat heater 904 is placed between the skin 903 and the cushion member 902 (see Patent Literature 1). The seat heater 904 is a sheet-shaped electric heater that warms a hip portion of an occupant through the skin 903. Also, it is a heater that warms the back.
In general, the seat heater 904 has a structure in which electric heating wires made of copper or the like are sewn or attached onto a fiber product such as nonwoven fabric.
In addition, in the conventional heating seat 901, the heat generated from the seat heater 904 transmits to the skin 903 through heat conduction, and warms the hip portion of the occupant. Meanwhile, a part of the heat generated from the seat heater 904 also transmits to the cushion member 902 through heat conduction, and thus, is used for increasing the temperature of the cushion member 902. Therefore, a portion of the electrical energy generated in the vehicle is not used for the original purpose of heating by the amount of the heat that transmits to the cushion member 902. Consequently, there was a problem that the fuel efficiency was lowered.
In order to suppress the heat transfer to the side of the cushion member 902, a structure in which a heat insulation material is placed between the cushion member 902 and the seat heater 904 has been proposed (Patent Literature 2). In Patent Literature 2, a vacuumed heat insulation material obtained by vacuum-sealing a core material, which is made of silica-based fibers such as such glass wool, with a laminate film is used as the heat insulation material. The heat insulation material prevents a part of the heat generated from the seat heater 904 from being released to the cushion member 902. It is expected that this causes an effect to promote the initial rise of the temperature of the side of the skin 903.
Furthermore, It is suggested that, by disposing, between the cushion member 902 and the seat heater 904, a heat insulation element having a heat conductivity smaller than that of the cushion member 902, the heat transfer from the seat heater 904 to the cushion member 902 can be suppressed, thereby realizing heating of the seat 901 with a smaller amount of the heat generation from a planer heating element.
It is considered that this has a great advantage since the heat generated in the seat heater 904 is effectively utilized, thereby improving the energy efficiency.
However, in the conventional configuration (Patent Literature 2), there is an effect to suppress the heat that is released to the cushion member 902, due to the heat insulation element between the cushion member 902 and the seat heater 904. However, since the heat is transmitted to an air layer included in the heat insulation element over the time, and is conveyed to the cushion member 902, there was a problem of heat loss.
With regard to a heating seat 901, the invention is to solve the above conventional problems, and relates to a heat insulation structure that suppresses heat transfer to a cushion member 902 provided in the seat 901, thereby providing a heating seat 901 with excellent heat efficiency.